Although after researching, it seems as though the cheaper non-battery powered passive glasses seem to produce the ghosting issues less frequently.
The synchronization between the 3D glasses and projector itself is often sighted as a possible source. Some projector owners even reported that while they experienced no crosstalk or distortion of the picture while watching a film, their guest sitting directly beside them had a completely different and obviously less satisfying viewing experience. This can all sound pretty frightening for 3D projector owners as there is nothing worse than sitting down with your new set up only to find that your movies and video games run with a headache-inducing double vision.
While the popularity of a three-dimensional home theater experience has maintained a steady fan base since the technology debuted in , it has simultaneously battled with the crosstalk problem. As the demand to keep 3D technology around persisted, the suppliers and its supporters have been looking for ways to cut down on the nuisance of ghosting.
Both of these groups have numerous resources and suggestions on how to tame your crosstalk to a manageable and almost unnoticeable level. Obviously, depending on the severity of crosstalk you are experiencing, some of these suggestions may not be the solution you are looking for.
As a quick reference, the following are a range of suggestions or possible rectifications:. The solutions listed above with the latter admitting submission but not defeat , range greatly price-wise and might not solve your specific problem. The 3D community is large, and they are continuing to come up with solutions to deafen the effects of crosstalk.
A 3D projector attempts to achieve an illusion that has only previously been accomplished by the human brain. There is no question that this would come with its hiccups and setbacks, the 3D crosstalk being one of these. Nevertheless, as the advancements in 3D technology continue to improve these systems, there is no doubt that eventually crosstalk will be a thing of the past. There are also active methods, such as using an eclipsing method of blocking the view of the other eye time-multiplexing , and interference technology of displaying two different images with two different wavelengths of light.
Worth mentioning is also the possibility of autostereoscopic displays, which enable stereoscopic viewing without glasses. Now that we understand the technological context, explanation of crosstalk is more tangible. This definition is good enough for communicating the general concept of crosstalk. However, for scientific conversation, it is much too ill-defined. In the following parts, the term and definition of crosstalk are subject to closer inspection.
Well known and widely used in the literature of stereoscopic displays, crosstalk as an effect is also known by other names and spellings Woods such as cross talk, cross-talk, leakage, extinction, extinction ratio, 3D contrast, and even x-talk.
Woods also points out a definition made by Huang et al. To be used as a metric, crosstalk has to be defined mathematically. Woods et al. They also point out that unfortunately, there exist several papers quoting crosstalk values, without specifying which definition is used.
This serves to strengthen the need for a standardized definition of crosstalk ratio. In this formula, leakage means the maximum luminance of light that leaks from the unintended channel to the intended channel, and signal means the maximum luminance of the intended channel. The measurements for luminance are achieved by measuring the level of black in the intended channel and the white in the unintended channel, which corresponds with leakage. In the same manner, signal correspondence is achieved by measuring the level of white in the intended channel and the level of black in the unintended channel.
These two definitions can be found from articles by Chu et al. Chu , Hong However because the earlier mathematical description of does not take into consideration the effect of black level, Woods et al. Nevertheless, crosstalk is a primary concern in developing stereoscopic display systems Daly One technology that is especially prone the crosstalk is anaglyphic 3D, whose main benefits are simplicity and cost.
Anaglyphic 3D systems are much rarer in these days, as active time- and polarization-multiplexed approaches tend to work better with lesser quality control. The level of filtering in anaglyphic 3D systems can vary considerably between different manufactured glasses, resulting in varying amounts of crosstalk Woods These are:.
Crosstalk is also present in other technologies. In addition to the presented technologies, there are also other 3D technologies, where crosstalk exist.
Similarly to anaglyphic and polarized 3D technologies, there are different factors between the technologies that have an effect on the amount of crosstalk. As a conclusion, it could be said that when designing a 3D technology-enabled experiences a decent amount of research should be dedicated to understanding the factors affecting the amount of crosstalk on that current approach.
The presence of crosstalk can lead to several problems such as general annoyance, visual discomfort, hindrance of fusing the images together, and breakdown of stereoscopic depth Daly , Woods At best, crosstalk is perceivable as a faint halo surrounding the edges of objects Daly and at worst it contains all of the previously mentioned problems. The amount of crosstalk is dependant on disparity and amplitude, with high levels resulting in ghosting Daly According to Daly et al with small disparities and low amplitudes, such as in textures, crosstalk is perceivable only as a blur.
With moderate amplitudes and disparities, crosstalk appears as tolerable double edges, while higher amplitudes can lead it to be displayed as an annoying ghost image. With even higher levels the double image disturbs stereoscopic fusion and prevents depth effect. Daly et al also point out other viewer experience such as general annoyance and discomfort, which can exist along with ghosting. Another description of the effect on viewer experience can be found from a paper by Xing et al Xing They also claim that comparatively few research efforts have been dedicated to this subject.
Their paper does indeed describe an extensive study on the subjective experience of crosstalk. The described study investigated how much crosstalk can be perceived when it is visible. If any trace of that previous frame is still present when the next frame is displayed to the viewer the result can be visible 3D cross talk. Note: LCD and LCoS micro-display chips inherently have a response time required to fully replace one image with the next image.
Projector manufacturers using these technologies typically insert a black frame or blanking frame in the video stream between right and left images in an attempt to remove the previous image before displaying the next image. Screen Characteristics — For active 3D systems the projection screen itself cannot be the source 3D crosstalk.
Using a low lamp mode or a user adjustable iris could also be employed as a means to reduce overall image brightness if you really find that desirable for 3D viewing. Synchronization between 3D Projector and 3D Glasses —3D is being projected as a sequence of alternating right and left images with a blanking interval between each image. The liquid crystal lenses of the active shutter 3D glasses must be synchronized with the projector such that the right lens only becomes transparent when the right images are displayed, the left lens only becomes transparent when the left images are displayed and these lenses become opaque all other times i.
If a given lens of the active shutter 3D glassed become transparent too soon or become opaque too late the 3D crosstalk will be the result. Note: With the increasing availability of 3 rd party universal active shutter 3D glasses, differences in the ability of the glasses to synchronize optimally with the projector can be observed.
Some such 3D glasses have a means to adjust the synchronization timing parameters to allow the user to select the best setting for use with their specific 3D projector or 3D TV. In the real world however the liquid crystal lenses never become perfectly transparent nor opaque. It is the inability of a lens to become full opaque that can lead to 3D crosstalk when even a very small percentage of the light is still being transmitted through the lens.
Note: It appears that 3D glasses being sold by the major projector manufacturers are improving in their ability to block light in the opaque state.
Some inexpensive third party 3D glasses may or may not be adequate in this characteristic. For Passive 3D projection systems there are two different technologies commonly used to visually separate the right and left image streams being seen by the viewers. I will be getting into passive 3D projection technologies and systems in a future blog.
The more common technique for passive 3D projection uses a different orientation for the polarization of the projected light associated with the right and left images streams e. High-end dual projector setups using polarization for 3D are available from such manufacturers as Runco.
The less common passive 3D technique uses narrow bandpass color filtering for the primary colors associated with the right and left image streams e. In either case, both the right and left images streams are typically for consumer systems displayed simultaneously, rather than sequentially, and the passive 3D glasses have lenses that must pass the desired image stream and effectively block the unwanted image stream.
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